Multi-audio

To test this feature and view the example code, please see the Android SDK 5 Example Code Quick Start guide.

Different audio tracks can be enabled when a stream is playing by calling the following methods on the OTVVideoView instance. Multi-audio features the same classes and calls as the Subtitles feature. However, there is always one audio track selected, whereas there can be no subtitles selected. OTVTrackInfo[] getOTVTrackInfo() returns an array of all tracks in the current stream, including audio and subtitle tracks.

The following audio track types are supported:

AAC-LC
HE-AAC
HE-AACv2

Prerequisites

A clear stream with an alternative audio track is available for testing.

Example code

The following example code is used to enable multi-audio tracks.

Audio tracks located by interrogating for tracks of type AUDIO

JAVA

    OTVTrackInfo[] trackInfo = mOTVVideoView.getOTVTrackInfo();
    for (int i = 0; i < trackInfo.length ; i++) {
      if (trackInfo[i].getType() == OTVTrackInfo.MEDIA_TRACK_TYPE_AUDIO) {
        // Add to audio track list with index 'i'
      } else if (trackInfo[i].getType() == OTVTrackInfo.MEDIA_TRACK_TYPE_TIMEDTEXT) {
        // Ignore track
      } else if (trackInfo[i].getType() == OTVTrackInfo.MEDIA_TRACK_TYPE_VIDEO) {
        // Ignore track
      }
    }
    // Return audio track list and indexes to present to the user for selection

To select a track at an index of the array returned by getOTVTrackInfo()

JAVA

mOTVVideoView.selectTrack(index);

Do not call selectTrack() if there is only one audio track as it is not supported and can lead to unexpected results.

To deselect a track at an index of the array returned bygetTrackInfo() (optional)

JAVA

mOTVVideoView.deselectTrack(index);

To implement a listener (ITrackChangedListener()) which is called whenever the track changes (optional)

JAVA

    mOTVVideoView.registerOnTrackChangedListener(mTrackchangedListener);
    // Create a Track changed listener
    private ITrackChangedListener mTrackchangedListener = new ITrackChangedListener() {
      @Override
      public void onTrackChanged() {
        // handle anything you want to do when a streams track changes
      }
    };

For details of the API calls used above, see the OTVVideoView class reference.